Hermit Crab

Hermit Crab Facts

Size	0.7-40 inch (2-100 cm)
Speed	Unknown
Weight	0.4-9 lb (0.2-4.1 kg)
Lifespan	5-30 years
Food	Fish, worms, plankton
Predators	Fishes, sharks, squids
Habitat	Coastal waters
Order	Decapoda
Superfamily	Hermit and coconut crabs
Scientific name	Paguroidea
Characteristics	Lives in a seashell

Main Characteristics

Hermit crabs are known for living in snail shells or other hollow items. This helps them to protect their soft and vulnerable abdomen. When they become too big for a snail shell or the shell gets damaged, they simply look for another one.

Hermit Crab Hermit Crab - Photo: marima/Shutterstock

Species

There are several families of hermit crabs:

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Land hermit crabs (Coenobitidae) with 15 species
Left-handed hermit crabs (Diogenidae) with about 350 species
Right-handed hermit crabs (Paguridae) with about 550 species
Deep-sea hermit crabs (Parapaguridae) with about 10 species
... and a few additional families we do not know much about yet.

Life Style

Are Hermit Crabs Loners?

The term hermit crab does not refer to their way of living, but to their habit of carrying their snail shell along wherever they go. They like to live in groups and even climb over one other.

Hermit Crab Hermit Crab - Photo: tae208/Shutterstock

Anatomy and Appearance

How Do Hermit Crabs Attach to Their Shell?

The hermit crab has two small legs which hold on to the shell.

The Biggest Hermit Crab

The largest hermit crab is the coconut crab. With a weight of 9 lb (4.1 kg) and a length of 40 inch (100 cm) from leg to leg, it is the largest terrestrial crab on earth. With its pincers it can even crack coconuts. Only the young Coconut crabs live in snail shells. Adults grow a shell themselves, because they do not find seashells in their size.

Hermit Crab Hermit Crab - Photo: Wollertz/Shutterstock

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Behavior

Hermit Crabs Fight for Shells

Hermit crabs often fight over snail shells. If they lose the fight and do not find another “home”, they even try to steal another crab’s shell.

You Can Help Hermit Crabs Survive

Do Not Collect Snail Shells

It is fun to collect snail shells, but you should consider that a hermit crab could be living in it. Even if the shell is empty, you should not take it away, because it could be a new home for a hermit crab. Without a shell, the crab will choke and dry out painfully. And there is another problem: In the course of their lifetime, the little creatures grow and need bigger and bigger snail shells. But particularly those are often sold to tourists as souvenirs. Help the crabs by not collecting or buying snail shells.

Hermit Crab Hermit Crab - Photo: tae208/Shutterstock

Fun Facts

Left- and Right-Handed

Hermit crabs can also be left- or right-handers. Yet, there is one difference: Either their left or right pincers are significantly bigger. Fortunately this is different with humans.